Vapor-dispersing devices are well known and include a variety of devices for vaporizing a liquid such as a perfume or insecticide into the surrounding environment. For example, vapor-dispersing devices include electrical devices with resistive heater modules and/or fans for driving liquids into the vapor phase, passive devices that rely on pads or wicks with large surface area for evaporating liquids without energy input, and simple aerosol sprays that propel and disperse liquids into fine droplets that evaporate in the air. Vapor-dispersing devices that are electrically powered are very common in home and institutional settings around the world. These devices may comprise a bottle of volatile liquid and they may operate by heat to volatize the liquid. Most common of these devices are air fresheners wherein a porous plastic wick is in communication with a bottle of scented fragrance oil and wherein the wick, continuously saturated with the fragrance, is placed in close proximity to a resistive heater element that accelerates the evaporation of the liquid from the wick. Another common configuration for a household air freshener comprises a bottle of scented fragrance oil with a porous plastic wick positioned in front of a fan. In these devices the fan moves air across the wick and the scented air is expelled into the immediate environment. These devices exist in the marketplace, both house current (110 v/220 v, AC) powered and battery powered (1.5 v, 3 v, 9 v, etc., DC). Exemplary devices include the Glade® Plugins® Scented Oil and Plugins® Scented Oil Fan air freshener products from S.C. Johnson & Son, Inc., and the Mobil'Air® Portable Electric Diffuser air freshener from Reckitt Benckiser. More elaborate products include piezoelectric devices wherein the scented fragrance oil is wicked up from a reservoir onto a vibrating plate where it is expelled into very fine droplets that quickly evaporate. One such device is the battery operated Glade® Wisp® Scented Oil Fragrancer air freshener from S.C. Johnson & Son.
In spite of the fact that fan, heater and piezoelectric air fresheners have dominated the marketplace over the last decade or so, there remain many limitations to such devices. Most problems relate to the fact that the wick remains in constant communication with the volatile liquid, and remaining continually saturated there is separation of fragrance components through what is nothing more than column chromatography. Invariably these devices slow down since the porous wicks clog with the less volatile ingredients and the spectrum of fragrance notes changes throughout the lifetime of the device.
We have invented a unique way to circumvent these limitations by keeping the porous member out from constant contact with the volatile liquid and keeping it from complete saturation. The way the present invention accomplishes this is by having a moveable piston that carries the porous member repeatedly into and out of the volatile liquid with each stroke. By changing from constant contact of the wick with the volatile liquid to repeated dipping, the evaporation of the liquid is more controlled and the distribution of the volatile components remains more constant throughout the evaporation of the liquid. The movement of the piston also serves as a bellow-means to expel the air treated with the volatile material into the environment.
Vapor-dispersing devices that contain pistons are extremely scant in the literature and are all based on movement of a piston to increase internal pressure within a reservoir to push liquid out. For example, U.S. Pat. No. 5,954,268 to Joshi, et al. and U.S. Pat. No. 5,776,561 to Lindauer both describe reservoirs that may be pressurized by depression of a piston and wherein the pressure forces liquid fragrance up a capillary tube and out onto an evaporative surface formed in the shape of a decorative flower.
U.S. Pat. No. 4,477,414 to Muramoto, et al. describes a piston operable device where depression of the piston forces liquid out through a capillary tube and onto an impregnation member where it evaporates. U.S. Pat. No. 6,923,383 to Joshi, et al. describes a device wherein a piston-actuated pressurization expels liquid through a restrictive opening. Lastly, piston actuated spray devices include the device described in U.S. Pat. No. 5,221,025 to Privas.
Devices that employ a bellows-type action to expel scented air include the devices described in U.S. Pat. No. 4,869,407 to Booth, et al.
None of these devices employ a moveable piston in a non-pressurized device for effecting the repeated dipping of a porous member into a volatile liquid so that the liquid is evaporated into the environment in a controlled manner.